Voltage Checks

[deserat]

Resistence Checks are fine.

Voltage checks that are off:

+275  is  260
kreg is 2.9

Thanks

[Paul Birkeland]

Are both Kreg voltages 2.9?  Are all other voltages spot on? Were you able to bias the 6C45's properly?

[deserat]

I'm sorry. In my world (software)  I'd consider my post a very poor bug report.

I don't recall the value of the initial voltage check which was done after building the  Power Supply Board but I do recall it was in range. Or I'da stopped then.

Resistance checks appear to be fine. Though I was concerned about some resistances until I understood that * meant that the resistance on the given terminal could be anything but zero. I was expecting it to leap around for each terminal based on the wording in the manual.  When it occurred to me that many of the terminals with * were attached to nothing and my volt meters ( I used two at this point as I thought there was a mistake ) were reading them as 0.0L.  If that is a wrong assumption then my resistances are totally wrong.

+275vDC on the Power Supply Board - reads 255 to 260
+6.3vDC on the Power Supply Board - reads 6.2 to 6.35
IA on the A side C 4 S Board - reads 255 to 260
IA on the B side C 4 S Board - reads 255 to 260
Breg Regulator Board (both sides) - reads 221
-reg Regulator Board (both sides) - reads 0.*
Kreg Regulator Board (both sides)  - 2.6 to 3.0

I have not attempted to adjust bias on the tubes... the words "highly regulated" scared me into thinking that a 100% + variation on the kreg was enough to be deeply concerned about it even if it is only 5 Volts.

[Paul Birkeland]

Go ahead and bias up those 6C45's, those voltages aren't particularly concerning.

[deserat]

Thanks. Am out of town for the weekend will get back on Tuesday.

[deserat]

Alright got the volt meter out tonight. 

Biasing the B side of the board let's me adjust voltage up to 265 and down to 240.
Biasing the A side fo the board has no impact.

Biasing the B side impacts both terminal 20 and 30.

[Paul Birkeland]

Yeah, there's an issue with the jumpering or construction of one or both of the boards.  You'll need to go through each step and check off what you have vs. what's in the manual.

-PB

[deserat]

By both of the boards which "Both" do you mean? I'm guessing you mean Power Regulator and  6C45P regulator.   Not the C4S 's.   Just trying to save myself some time and focus on the most likely suspects.

[Paul Birkeland]

By "both" boards, I meant both the high current C4S boards and the center C4S/bias board.  The PC board over the power transformer does not need to be examined.

-PB

[deserat]

Excellent. Thank you.

[deserat]

OK so I walked through all the boards again.  The two C4S boards match up. The center board had two mistakes in it. Well 1 mistake twice and 1 soldered jumper lead. I soldered the unattached lead. I want to make sure that the way I plan to solve the other mistake is appropriate. 

I managed to skip right over the red text telling me to attach the lead under the screw to the center lead on the trim pots. I'm guessing I can simply clean and trim one of the scrap leads from the build and create the bridge.  Is that an appropriate solve or should I find and order new trim pots?

[deserat]

Went ahead with soldering a spare lead between the Pot leads. Resulted in proper readings off main power supply board. 275 VDC. 6.3 is still 6.3

Breg still 220VDC
-reg still 0

Kreg now 10 VDC
 IA on both A and C sides  240 VDC.
Biasing  ranges from 240 to 160

B side trim adjustment still affects 20 and 30.
A side trim adjustment still does nothing.

Assuming solution is still RTFM.  So back to RTFMing... but communicating progress just in case.

[Paul Birkeland]

It looks like you're getting closer. When you said your biasing range of voltages, that is still only on one side?

[deserat]

Ya.  Only one side of the board affects voltage for both 20 and 30.   If you can know of particular board or interboard connections I should focus on I'd appreciate it. I only get an hour or so at night to debug at night when I can, which makes focused methodical debugging somewhat difficult.

thanks
-v

[Paul Birkeland]

Sometimes it can help to print out the assembly steps in the manual.  There are PDF printing options to print two of the manual pages per sheet of paper.  As you check each step, you can just mark it off with a pen.

The other option is to send your Mainline in for a flat rate repair.  Having repaired a few Mainlines myself, I can say that my debugging process for figuring out what was going on in each case was to just work through the manual until I found the improper connection(s).

-PB